PHOTOSENSITIZED CATIONIC POLYMERIZATION USING ALLYL SULFONIUM SALT

The cationic polymerization of cyclic ethers such as cyclohexane oxide (CHO) and vinyl monomers such as butyl vinyl ether (BVE) and N-vinylc arbazole (NVC) is initiated upon irradiation at lambda 380 nm in CH2Cl 2 solution containing an allylic sulfonium salt, namely, 2-ethoxycarbo nyl-2-propenylthiophenium hexafluoroantimonate (1) (EMT(+) SbF6-), and one of the following compounds: benzophenone, anthracene, thioxanthon e, perylene or phenothiazine. Electron transfer and hydrogen abstracti on mechanisms were proposed for the initiation step. Stable cation rad icals of phenothiazine were also prepared, and the cationic polymeriza tion of butyl vinyl ether was initiated by these cation radicals.